4,234 research outputs found
Boundary effects on the scaling of the superfluid density
We study numerically the influence of the substrate (boundary conditions) on
the finite--size scaling properties of the superfluid density in
superfluid films of thickness within the XY model employing the Monte Carlo
method. Our results suggest that the jump at the
Kosterlitz--Thouless transition temperature depends on the boundary
conditions.Comment: 2 pages, 1 Latex file, 1 postscript figure, 2 style file
Assessing moisture in porous traditional building materials
Historic England is often asked for advice on damp problems in historic and traditional buildings. Whilst many different methods are commonly used to assess damp problems in walls, all have some drawbacks. There is lack of agreement over how they should be used and little information about how they compare one with another. This project developed a common methodology in the laboratory to compare the performance of a range of invasive and non-invasive moisture measurement methods used to assess moisture in porous masonry. The findings suggested that most of the measurement techniques can provide good semi-quantitative estimates of moisture levels in porous traditional building materials
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Meteorological and chemical factors controlling ozone formation in Seoul during MAPS-Seoul 2015
To understand the chemical mechanisms of controlling factors in ozone (O3) formation in early summer in Seoul, a comprehensive study encompassing measurement and modeling was conducted under the Megacity Air Pollution Study-Seoul (MAPS-Seoul) campaign. From May 18 to June 12, 2015, O3 and peroxyacetyl nitrate (PAN) were measured, along with their precursors, including NOx and volatile organic compounds (VOCs), at the Korea Institute of Science and Technology, located in northeast Seoul. VOCs were sampled in a canister twice a day (at 09:30 and 15:00) and analyzed via gas chromatography. The meteorological conditions and chemical regimes of the air masses were clearly distinguished during the study period. In May, NOx concentrations were higher with more pronounced diurnal cycles of precursors and O3 under constant westerly winds. By contrast, stagnant conditions developed in June, which reduced the inflow of primary emissions from the downtown area but increased the influence from the neighboring forest under high temperatures. As a result, the ratio of O3 to odd oxygen was higher in June, indicating a less efficient removal of O3 by NOx. In the same context, the air mass was chemically more aged with a higher NO2/NOx ratio and enhanced OH reactivity of oxygenated and biogenic VOCs in June. The overall measurement results suggest that O3 formation is slightly more sensitive to VOCs than to NOx in Seoul during this season, when O3 concentrations are the highest of the year
Sorting live stem cells based on Sox2 mRNA expression.
PMCID: PMC3507951This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.While cell sorting usually relies on cell-surface protein markers, molecular beacons (MBs) offer the potential to sort cells based on the presence of any expressed mRNA and in principle could be extremely useful to sort rare cell populations from primary isolates. We show here how stem cells can be purified from mixed cell populations by sorting based on MBs. Specifically, we designed molecular beacons targeting Sox2, a well-known stem cell marker for murine embryonic (mES) and neural stem cells (NSC). One of our designed molecular beacons displayed an increase in fluorescence compared to a nonspecific molecular beacon both in vitro and in vivo when tested in mES and NSCs. We sorted Sox2-MB(+)SSEA1(+) cells from a mixed population of 4-day retinoic acid-treated mES cells and effectively isolated live undifferentiated stem cells. Additionally, Sox2-MB(+) cells isolated from primary mouse brains were sorted and generated neurospheres with higher efficiency than Sox2-MB(-) cells. These results demonstrate the utility of MBs for stem cell sorting in an mRNA-specific manner
Decentralised Learning MACs for Collision-free Access in WLANs
By combining the features of CSMA and TDMA, fully decentralised WLAN MAC
schemes have recently been proposed that converge to collision-free schedules.
In this paper we describe a MAC with optimal long-run throughput that is almost
decentralised. We then design two \changed{schemes} that are practically
realisable, decentralised approximations of this optimal scheme and operate
with different amounts of sensing information. We achieve this by (1)
introducing learning algorithms that can substantially speed up convergence to
collision free operation; (2) developing a decentralised schedule length
adaptation scheme that provides long-run fair (uniform) access to the medium
while maintaining collision-free access for arbitrary numbers of stations
Scaling of the superfluid density in superfluid films
We study scaling of the superfluid density with respect to the film thickness
by simulating the model on films of size ()
using the cluster Monte Carlo. While periodic boundary conditions where used in
the planar () directions, Dirichlet boundary conditions where used along the
film thickness. We find that our results can be scaled on a universal curve by
introducing an effective thickness. In the limit of large our scaling
relations reduce to the conventional scaling forms. Using the same idea we find
scaling in the experimental results using the same value of .Comment: 4 pages, one postscript file replaced by one Latex file and 5
postscript figure
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‘If you look the part you’ll get the job’: should career professionals help clients to enhance their career image?
This article presents a critical exploration of the role of career professionals in supporting people to reflect on and enhance their appearance, attractiveness and self-presentation (career image). The article is conceptual and based on a review of the broader literature on career success, appearance and attractiveness. It explores the evidence for a relationship between attractiveness and career, and the authors propose a conceptual framework in which career image is comprised of three elements (interpersonal skills, aesthetic presentation and beauty). The paper examines a possible role for career professionals in relation to this and then critically examines this role and concludes with the proposition of a research agenda in this area
A Novel Liver-targeted Testosterone Therapy for Sarcopenia in Androgen Deprived Men With Prostate Cancer.
Objective: Androgen deprivation therapy (ADT) reduces muscle and bone mass, increasing frailty in men with prostate cancer. The liver mediates the whole body anabolic effects of testosterone. Based on first-pass metabolism, liver-targeted testosterone treatment (LTTT) entails oral delivery of a small dose of testosterone that does not raise peripheral blood testosterone levels. LTTT reduces blood urea and stimulates protein anabolism in hypogonadal men and postmenopausal women. We investigated whether LTTT prevents loss of lean and bone mass during ADT. Method: A 6-month, double-blind, placebo-controlled study of testosterone 40 mg/day in 50 men. Primary outcome measures were lean mass and bone mineral content (BMC). Testosterone, urea and prostate-specific antigen (PSA) were monitored. Patients were withdrawn if PSA exceeded 4 ng/mL. Results: 42 patients completed the study. Mean (95% CI) testosterone rose during LTTT but not placebo treatment [∆ 2.2 (1.3-3.0) vs -0.7 (-1.5 to 0.2) nmol/L; P < 0.01]. Mean PSA level did not change significantly during either treatment. Blood urea fell [∆ -0.4 (-0.9 to -0.1) mmol/L] during LTTT but not placebo [∆ 0.05 (-0.8 to 0.9) mmol/L]. BMC [∆ 49 (5 to 93) g; P < 0.02] and lean mass [∆ 0.8 (-0.1 to 1.7) kg; P = 0.04) increased compared to placebo. Five patients on LTTT withdrew from increased PSA levels, all returning to baseline levels. Conclusion: LTTT shows promise as a simple therapy for preventing sarcopenia and bone loss during ADT. LTTT may induce reversible PSA rise in some patients. Further studies are required to optimize LTTT dose in ADT. LTTT has potential application in other catabolic states in men and women
Angle-resonant stimulated polariton amplifier
We experimentally demonstrate resonant coupling between photons and excitons in microcavities which can efficiently generate enormous single-pass optical gains approaching 100. This new parametric phenomenon appears as a sharp angular resonance of the incoming pump beam, at which the moving excitonic polaritons undergo very large changes in momentum. Ultrafast stimulated scattering is clearly identified from the exponential dependence on pump intensity. This device utilizes boson amplification
induced by stimulated energy relaxation
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